Why fuse in computer power cables(leads)

  • Thread starter Thread starter nagesh_pandher
  • Start date Start date
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nagesh_pandher

In India power leads for computers do not have any fuse in them, 5amp
or 13amp.

Do not know about USA but in UK these leads have fuse in them, mostly
5amp.

What can happen in a Computer that will cause fuse in cable to blow up?

HP sells its servers with power cable that cannot have fuse in the
cable.

What could be HP's assumption?
 
In India power leads for computers do not have any fuse in them, 5amp
or 13amp.

Do not know about USA but in UK these leads have fuse in them, mostly
5amp.

What can happen in a Computer that will cause fuse in cable to blow up?
shorts

HP sells its servers with power cable that cannot have fuse in the
cable.
Click to expand...

that probably varies by country to satisfy local laws
What could be HP's assumption?
Click to expand...
it's probably following the law
 
CJT said:
that probably varies by country to satisfy local laws

it's probably following the law
Click to expand...

I think you will find the fuse is also there to protect the cable as well
encase its cut through or a short on the cable the fuse does not just
protect the computer
 
Kevin R said:
I think you will find the fuse is also there to protect the cable as well
encase its cut through or a short on the cable the fuse does not just
protect the computer
Click to expand...

Dont forget the UK has a lot of ring main GPO ccts, so thats why they use
the fused plugtops.
 
In the environment of Datawarehouse chances of cable getting cut and
short circuiting should be highly unlikely.
 
Can you please explain "ring main GPO ccts"?
I am totally nontechnical.

Regards
Nagesh
 
up?



Short circuiting in a cmputer that is running continuously for years in
Datawarehouse should be very rare I believe.
Click to expand...
That's why the fuses don't blow very often.
 
CJT said:
that probably varies by country to satisfy local laws

it's probably following the law
Click to expand...
Probably due to India having Fault-current-relays? like rest of Europe,
not the deadly dangerous anitique system as in UK. Detects if current is
equal in & out of house (live & 0 wires)....if greater than treshold
(like if you grap the live wire, mine´s 30 mA) it trips & saves your
life.....not needing it to be a true shortcuirt.

Normally dont reply on such a X-poster...but hey why not might save his
life :))))))))

Best regards

ChipMIK, expecting some serious shouting from you UK-guys :)
 
Probably due to India having Fault-current-relays? like rest of Europe,
not the deadly dangerous anitique system as in UK. Detects if current is
equal in & out of house (live & 0 wires)....if greater than treshold
(like if you grap the live wire, mine´s 30 mA) it trips & saves your
life.....not needing it to be a true shortcuirt.
ChipMIK, expecting some serious shouting from you UK-guys :)
Click to expand...
Too true - my personal opinion is that the UK is an awful lot safer than the
US.
Current imbalance trips are pretty standard around here (south uk);
individually fused plugs; plugs that make it diffcult to disconnect by just
pulling the cable;
man sized 240V instead of the wimpy 110v ... ;)))
tee hee
Neil
 
Neil said:
Too true - my personal opinion is that the UK is an awful lot safer than
the US.
Click to expand...

Don't look now but US building codes _require_ ground fault interrupters
anywhere that there's a significant risk of a short to something other than
the neutral.
Current imbalance trips are pretty standard around here (south uk);
individually fused plugs; plugs that make it diffcult to disconnect by
just pulling the cable;
man sized 240V instead of the wimpy 110v ... ;)))
Click to expand...

Hey, we've got all the 240 we want. We just don't waste it on clock radios
and electric pencil sharpeners.

Normal residential service in the US is 240. We split it to get two 120V
phases, but the 240 is there any time we have a real use for it.

The simple fact is that you Brits are going to defend your quaint way of
life to the death, and that's as it should be.
 
Can you please explain "ring main GPO ccts"?
I am totally nontechnical.
Click to expand...

Here is some explanation of UK wiring (from www.epanorama.net):

UK wiring is somewhat special case. The UK is unusual in having fused
plugs as standard (according BS1363 parts 2 and 4). 13A max in
eachplug, and 30A at the panel for each ring. Maximum current at wall
outlet in the UK is for 13A. The plugs carry a fuse holder and the
fuse should be rated to suit the appliance used (fuse rating from 1A
up to 13A exist). The fuse in the plug is for protecting the cable to
the appliance, not the appliance itself. For the latter, the appliance
would have its own fuse (or other suitable protection means). Neutral
is neither switched nor "protected". UK mains plugs are polarized. In
the UK, a wiring system known as a ring mains is used. UK standard
(for the last 30 years or so) has been the ring -main (domestic and
commercial) rated at 30/32A @230V. A single cable runs all the way
round part of a house interconnecting all of the wall outlets. This
will be protected by one large fuse in the fuse box. A typical house
will have three or four such rings. The power rings are normally
protected by a 30 amp fuse and the lighting rings by 5 or 10 amp
fuses. Those fuses protect the wiring, not the appliances so, every
appliance carries its own fuse in the plug.


The design philosophy of e.g. the German system (Schuko) is that a room
(or a small number of rooms) has a 10 A or 16A fuse in the consumer
unit, and all leads and plugs are designed to withstand any
short-circuit current that will not yet blow the fuse (today usually
circuit breakers are used, not fuses). If a fault occurs, a circuit
breaker is trivial to reset, The fuses are generally in the main
distribution panel. The fuse inside equipment will provide the
protection agains constant overload. This equipment fuse is rated
based on the power the equipment might take, and the wire
going to equipment must be thick enough to handle that load current
that this fuse can pass before breaking.
 
In comp.sys.ibm.pc.hardware.storage Tomi Holger Engdahl said:
(e-mail address removed) writes:
Click to expand...
Here is some explanation of UK wiring (from www.epanorama.net):
Click to expand...
UK wiring is somewhat special case. The UK is unusual in having fused
plugs as standard (according BS1363 parts 2 and 4). 13A max in
eachplug, and 30A at the panel for each ring. Maximum current at wall
outlet in the UK is for 13A. The plugs carry a fuse holder and the
fuse should be rated to suit the appliance used (fuse rating from 1A
up to 13A exist). The fuse in the plug is for protecting the cable to
the appliance, not the appliance itself. For the latter, the appliance
would have its own fuse (or other suitable protection means). Neutral
is neither switched nor "protected". UK mains plugs are polarized. In
the UK, a wiring system known as a ring mains is used. UK standard
(for the last 30 years or so) has been the ring -main (domestic and
commercial) rated at 30/32A @230V. A single cable runs all the way
round part of a house interconnecting all of the wall outlets. This
will be protected by one large fuse in the fuse box. A typical house
will have three or four such rings. The power rings are normally
protected by a 30 amp fuse and the lighting rings by 5 or 10 amp
fuses. Those fuses protect the wiring, not the appliances so, every
appliance carries its own fuse in the plug.

The design philosophy of e.g. the German system (Schuko) is that a room
(or a small number of rooms) has a 10 A or 16A fuse in the consumer
unit,
Click to expand...

That fuse would be in the fuse box on tha wall. 10A for light, 16A
for power outlets and e.g. 3*25A for an electric stove.
and all leads and plugs are designed to withstand any
short-circuit current that will not yet blow the fuse (today usually
circuit breakers are used, not fuses). If a fault occurs, a circuit
breaker is trivial to reset, The fuses are generally in the main
distribution panel. The fuse inside equipment will provide the
protection agains constant overload. This equipment fuse is rated
based on the power the equipment might take, and the wire
going to equipment must be thick enough to handle that load current
that this fuse can pass before breaking.
Click to expand...

Actually there is no requirement for a fuse in the equipment itself,
depending on what type of equipment it is and what kind of cable it
has. If it has 1.5mm^2 cabeling, then the main fuse is enough, since
the wires in the wall are also 1.5mm^2 and these are rated for 16A
continous current and several thousands for a short duration
short-circuit. It is also permissible to use lighter cables
(0.75mm^2) for lighter equipment. This type of cable should
still be able to stand 16A for some time.

For the british system in equipment without a fuse in the plug
you would need something like 1.5mm^2 cables to all types of
equipment. A 0.75mm^2 cable would likely have problems at 32A.
Remember that power goes with the square of the current in
cables, so the 0.75mm^2 cable would actually get heated up
four times as trong as it would in germany with current that
just about does not blow the fuse.

As a result the british need additional fuses in thinner cables.
I would guess that for 2.5mm^2 cables the british can do without
the fuse in the plug.

Arno
 
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